How login works?

Hi Seth,

I was able to change the redirect url.

But stuck up now in last step of validation. When user enters wrong credentials, page should be redirected to logon page( this part is done) and display an error message saying wrong credentials entered and force the user to enter correct credentials. How could I write this functionality? Error message box is ready but what is the query to execute and check whether user entered correct or wrong credentials?

thanks